Despite the incredible evolution in cloud-native technologies, DevOps tooling, and deployment automation, many traditional banks and financial institutions still face downtime during application releases — even in 2025. It’s a persistent problem that plagues customer experience, halts critical services, and contradicts everything modern software delivery stands for.

So why do these mission-critical, heavily-funded systems still fail to achieve zero-downtime deployments?

Let’s break down the reasons — layer by layer.

1. Monolithic Architectures and Tightly Coupled Releases

At the heart of many banking systems lies a monolith — a giant, entangled application where components are deeply intertwined. In such a setup, even minor code changes in one module can ripple across the entire system, making isolated deployments impossible.Imagine updating the loan interest calculation logic, but needing to stop the entire banking platform — from net banking to ATM services — just to push the change.Without microservice boundaries or modular abstractions, there’s no service isolation, no independent deployments, and certainly no way to update or scale just one feature or module. This directly violates core DevOps principles like modularity, independence, and deployability.

Banks often cite regulatory compliance, legacy investments, or perceived risk in transitioning to microservices — but inaction has its own cost: downtime and lost trust.

2. Lack of CI/CD Maturity

While startups and digital-first companies have embraced mature CI/CD pipelines, many banks are still stuck with outdated deployment practices:

Manual change approvals

Weekend releases with full system freeze

Rollback via backup restore, not versioning

Modern pipelines can do so much more. For instance:

Blue-Green Deployments: Route traffic between two identical environments to cut over without impact.

• Canary Releases: Gradually roll out new features to a subset of users to monitor performance.

• Progressive Rollouts: Release in stages — by geography, customer segment, or risk profile.

These practices minimize risk and eliminate downtime, but only if the underlying delivery pipeline supports them.

Unfortunately, many legacy teams either lack the tooling, cultural mindset, or governance flexibility to implement this effectively.

3. Absence of Feature Flags

In modern DevOps workflows, feature flags allow teams to deploy code safely without enabling it immediately. This decouples deployment from release, letting teams test in production, gather metrics, and gradually expose features.

But in many banking setups, the absence of feature flags means:

• Every deployment is also a release.

• There’s no way to disable or hide a buggy feature after deployment.

• Teams are forced into high-risk, all-or-nothing deployments.

This creates an operational nightmare — leading to scheduled downtimes, hotfix chaos, and rollback disasters.

The solution? Embrace feature flagging platforms like LaunchDarkly, Flagsmith, or even open-source tools like Unleash — but again, cultural resistance and tooling inertia often block the path forward.

4. Databases Without Online Migrations

Even if your app is built for zero-downtime, your database might not be.

In many banks, the backend still relies on:

• Legacy RDBMS like Oracle or Mysql

• Huge, shared schemas with no isolation

• Synchronous schema changes done during off-hours

This leads to scheduled maintenance windows just to add a column or modify an index.

Modern practices favor online schema migration tools such as

• pt-online-schema-change for MySQL

• Liquibase or Flyway for versioned migrations

• Ghost or gh-ost for non-blocking updates

But many financial systems have databases so old, customized, or undocumented that even applying these tools becomes a risky proposition.

So Why Are Banks Still Behind?

1. Risk Aversion and Compliance Overhead

Banks are inherently conservative. With regulatory bodies watching, they prefer slow, risk-free progress over innovation.

2. Legacy Talent and Organizational Silos

Many engineers still working on core banking systems are more familiar with COBOL than Kubernetes. Cross-functional DevOps teams are rare; teams work in silos with little ownership over end-to-end delivery.

3. Technical Debt Accumulated Over Decades

Transitioning to microservices, adopting GitOps, or enabling cloud-native workflows often requires massive rewrites. It’s not just a tech upgrade — it’s an entire culture shift.

Conclusion: Zero Downtime is a Choice — and a Journey

By 2025, zero-downtime delivery is technically achievable for almost any industry — but organizationally difficult for traditional banks.

To succeed, banks must:

• Invest in platform engineering and CI/CD enablement

• Incrementally decouple services and databases

• Modernize through patterns like strangler fig migration

• Embrace DevOps culture — not just DevOps tools

Until then, scheduled downtimes will remain the unfortunate norm — and customers will keep asking: “Why is my bank always under maintenance?”